The present invention relates to hair rollers, particularly to hair rollers of the type having bristles designed to hold the roller wound in a lock of hair without resort to supplementary fasteners such as clips or bobby pins.
A variety of hair rollers of this kind are known. One such roller is disclosed in U.S. Pat. No. 3,556,114 issued Jan. 19, 1971 to S. M. Simon and assigned to the assignee hereof. Such rollers achieve their purpose effectively, but have shortcomings. Rollers as described in the Simon patent have a cylinder of plastic material from which many hair-retainers project. Those retainers are made of monofilaments of nylon formed into base loops embedded in the cylinder wall and projecting loops, and one leg of each projecting loop is cut by a sharp blade, thus forming a retainer and a stub. The hair retainer adjacent the stub has proved to be so secure as to make it sometimes difficult to remove the roller from the wearer's hair. The short stub projecting outward of the cylinder wall of the roller is irritating when the roller is pressed against the wearer's head, and irritating to the user's hands when manipulating the roller.
Other hair rollers are known having variously shaped bristles intended to render the rollers self-retaining. For example, rollers have been proposed having projecting elements on a cylinder, all of one-piece molded plastic. (See German Gebrauchsmuster No. 1,800,352.) However, it is evidently difficult if not impossible to mold such elements thin enough to simulate yielding filaments, and it is all-but-impossible to mold vast numbers of such elements projecting from the cylinder in all directions outward of the cylindrical axis.
In another example, a commercial form of roller (see U.S. Pat. No. 3,123,080) includes a cylinder of woven fabric from which monofilamentary elements project which are formed as loops cut at their apices. The resulting bristles emerge from the fabric in pairs, each pair emerging at virtually the same spot. They are of "partial elliptical shape" and resemble face-to-face parentheses, thus: (). Retention of such bristles in the hair is poor, and there is a conflict between making such bristles stiff enough to be forced into the hair yet not so stiff as to be irritating when pressed against a wearer's scalp or when being handled.
An object of this invention resides in providing a novel hair roller that is economical and practical to produce, combining desirable properties of a self-retaining roller.